steam clown™ productions · •convert a logical expression in to a truth table •what you will...

© Copyright 2017 STEAM Clown™

STEAM Clown™

&Productions

STEAM Clown™ Productions

Logic Gates – Building a Safety circuit


STEAM Clown™

&Productions


See Appendix A, for Licensing & Attribution informationby-nc-sa-3.0

https://creativecommons.org/licenses/by-nc-sa/3.0/

https://creativecommons.org/faq/#what-does-some-rights-reserved-mean


https://creativecommons.org/faq/#what-does-some-rights-reserved-mean


STEAM Clown™

&Productions

• Prior Knowledge• Explain the difference between AND, OR, NOT logic gates • Read and fill out a Truth Table• Convert a Logical Expression in to Gate Diagram• Convert a Logical Expression in to a Truth Table

• What You Will Know & Be Able To Do• Identify the components and signals that are used in a Robot work cell

safety circuit• Prioritize signals and make sure the Emergency Stop really stops• Build a logic circuit that integrates signals from sensors and safety devices

What You Will Know…


STEAM Clown™

&Productions

•Workcell

•Tooling

•Workpeice

New Words


STEAM Clown™

&Productions


Robot Work Cell Safety


STEAM Clown™

&Productions

What needs to be safe?

• People are always the #1

• Prioritized Safety•People•Robot•Work Cell• Tooling•Workpeice


STEAM Clown™

&Productions

•Emergency Stop Buttons

•Deadman Switch

•Hard Stop or Limit Switch's

•Light Curtain, Pressure Pads, Cameras, etc

• Interlocks (Keys and Lockouts)

• Interlocks (gates and doors)

•

Devices that feed a safety Logic Circuit


STEAM Clown™

&Productions

Emergency's

• This signal needs to be the highest priority…

• Needs to override any other signals

• Needs to be immediate


STEAM Clown™

&Productions

DeadMan

• Next in priority after Emergency Stop

• If this switch is released, the robot needs to stop any motion


STEAM Clown™

&Productions

Things that detectHumans…

• Light Curtains

• Pressure Pads

• Motion Sensors

• Cameras


STEAM Clown™

&Productions

Interlocks

• Control Panels with Keys

• Gates with Keys

• Gates with Switches

• Limit Switches


STEAM Clown™

&Productions

Bootup, Diagnostics, Status

• Power good signal

• Motor diagnostic pass

• Memory and processor diagnostic pass

• I/O signals in correct state (user defined)

• All safety signals in their "safe" state (see above)


STEAM Clown™

&Productions


Organizing Priority


STEAM Clown™

&Productions

Robot Work Cell


STEAM Clown™

&Productions

Let’s Organize the Signals


STEAM Clown™

&Productions

Binary Logic Function

Operators ( +, •, ‘ )

Variables

Constants ( 0, 1 )

Groupings (parenthesis)

F(var) = expression

This is a set of Binary variablesDefines the set of “Inputs”

Ex: F(a,b) = (a’•b) + b’

F(a,b,c) = a•((b+c’)+(b’+c))

ab

F= (a’•b) + b’


STEAM Clown™

&Productions

Emergency Stop

• If any of the E-Stop buttons are pushed, then the AND gate is OFF

+2-Input AND

A B F=A•B

0 0 0

0 1 0

1 0 0

1 1 1


STEAM Clown™

&Productions

Deadman Switch

• If the Deadman Switch is pushed, then the OR gate is ON

+A B F=A+B

0 0 0

0 1 1

1 0 1

1 1 1

2-Input OR


STEAM Clown™

&Productions

Other Sensors

• Depending on the Sensor, the logic will be asserted HIGH or LOW +

+


STEAM Clown™

&Productions

Create a Logic Circuit for your inputs

Emergency Stop #1

Emergency Stop #2

Pressure Pad (not pushed)

Motor Diagnostic (Low)

Gate Closed

https://logic.ly/demo/

https://logic.ly/demo/


STEAM Clown™

&Productions


Reference Slides


STEAM Clown™

&Productions

Basic AND & OR Logic Operators

1-bit logic AND resembles binary multiplication:

0 • 0 = 0

0 • 1 = 0

1 • 0 = 0

1 • 1 = 1

1-bit logic OR resembles binary addition, except for one operation:

0 + 0 = 0

0 + 1 = 1

1 + 0 = 1

1 + 1 = 1 (≠ 102)AB

F= A + B

AB

F= A • B


STEAM Clown™

&Productions

•Logic gates are abstractions of electronic circuit components that operate on one or more input signals to produce an output signal

Logic Gates

aa

bF= a • b

AND bF= a + b

OR a aINV


STEAM Clown™

&Productions

AND Gate

• This AND gate has two inputs and an output

• Output is zero unless both Inputs are 1’s

A B F=A•B

0 0 0

0 1 0

1 0 0

1 1 1

a

bF= a • b

AND

2-Input AND

Truth table: tabular form that uniquelyrepresents the relationship between theinput variables of a function and its output

The AND operation is mathematically defined as the product of two Boolean values


STEAM Clown™

&Productions

OR Gate

• This OR gate has two inputs and an output

• Output is 1 if any of the Inputs are 1’s

A B F=A+B

0 0 0

0 1 1

1 0 1

1 1 1

a

bF= a + b

OR

2-Input OR


The OR operation is mathematically defined as the summation of two Boolean values


STEAM Clown™

&Productions

NOT (Inverter) Gate

• This NOT gate has one input and one output

• This is an “inverter” function

• Output is 1 if the Input is 0, and 0 if the Input is 1

(Inverter)NOT


a F= a

0 1

1 0

a F= aINV


STEAM Clown™

&Productions

Truth Tables for logic operators

2-Input AND

A B F=A+B

0 0 0

0 1 1

1 0 1

1 1 1

2-Input OR

A F=A’

0 1

1 0

NOT

Truth table: tabular form that uniquely represents the relationship between the input variables of a function and its output

A B F=A•B

0 0 0

0 1 0

1 0 0

1 1 1


STEAM Clown™

&Productions

AND Gate + Inverter

• This NAND gate has two inputs and an output

• Output is 1 unless both Inputs are 1’s, then it’s 0

A B F=A•B

0 0 1

0 1 1

1 0 1

1 1 0

a

b

c = a • b

AND

2-Input NAND

F= ca

bF= a • b

NAND=


STEAM Clown™

&Productions

NAND Gate

• This NAND gate has two inputs and an output

• Output is 1 unless both Inputs are 1’s, then it’s 0

A B F=A•B

0 0 1

0 1 1

1 0 1

1 1 0

2-Input NAND


The NAND operation is mathematically defined as the product of two Boolean values

a

bF= a • b

NAND


STEAM Clown™

&Productions

NOR Gate

• This NOR gate has two inputs and an output

• Output is 0 if any of the Inputs are 1’s

A B F=A+B

0 0 1

0 1 0

1 0 0

1 1 0

2-Input NOR


The NOR operation is mathematically defined as the summation of two Boolean values

a

bF= a + b

NOR


STEAM Clown™

&Productions

XOR Gate

• This XOR gate has two inputs and an output

• Output is 1 if the Inputs are different

A B F=A B

0 0 0

0 1 1

1 0 1

1 1 0

a

bF= a b

XOR

2-Input XOR


The XOR operation is mathematically defined as the summation of two Boolean values if they are different

+

+


STEAM Clown™

&Productions

•Learning about Logic Gates and Circuits• https://logic.ly/lessons/

Check Out This Logic Link

https://logic.ly/lessons/


STEAM Clown™

&Productions


Appendix


STEAM Clown™

&Productions

Appendix A: License & Attribution

• This interpretation is primarily the Intellectual Property of Jim Burnham, Top STEAM Clown, at STEAMClown.org

• This presentation and content is distributed under the Creative Commons License CC-by-nc-sa-3.0

• My best attempt to properly attribute, or reference any other sources or work I have used are listed in Appendix B


http://www.steamclown.org/


STEAM Clown™

&Productions

•Power Point Logic Gates Symbols – Oliver Mannay

•Slide Share Logic Gates

•PPT from Michigan Tech EE 4271

Appendix B: Attribution for Sources Used

https://www.tes.com/teaching-resource/logic-gate-symbols-for-powerpoint-11139006

http://slideplayer.com/slide/1653316/

http://www.ece.mtu.edu/faculty/shiyan/EE4271Fall16/DigitalLogic.ppt

steam clown™ productions · •convert a logical expression in to a truth table •what you will...

Documents